1. Field of the Invention
This invention relates to the discovery that the prokaryotic enzyme, aminoglycoside 3"-adenyltransferase (AGAT), in particular as encoded by a bacterial aadA gene, is useful as a selectable marker for transformed plants. The enzyme conveys resistance to spectinomycin and streptomycin. Such markers are particularly advantageous because they are non-lethal, provide rapid visual identification of transformed cells and permit selection in media containing either spectinomycin or streptomycin. In addition, AGAT may be used as a selectable marker which differentiates by enabling survival on selective media.
Specifically, this invention discloses vectors for transforming the plants with the prokaryotic transferase, plants containing the transferase and methods for selecting plants transformed with vectors having DNA sequences encoding bacterial adenyl transferases.
2. Information Disclosure
Bacterial resistance to spectinomycin and streptomycin based upon aminoglycoside 3"-adenyltransferase is known. Chinault, A.C., 1986, Plasmid 15, 119-131, 1986.
Bacterial genes for resistance to antibiotics have been expressed in plants, including kanamycin, Bevan, et al., Nature, 304:184-187, 1983, and Fraley, et al., Proc. Nat'l. Acad. Sci., USA, 80, 4803-4807, 1983; hygromycin, Rothstein, et al., Gene, 53:153-161, 1987; methotrexate, Eicholtz, et al., Somatic Cell and Molecular Genetics. 13:67-76, 1987; gentamicin, Hayford, et al., Plant Physiol., 86, 1216-1223, 1987; and streptomycin, Jones, et al., Mol. Gen. Genet., 210 (1):86-91, 1987, and Maliga, p , et al., Mol. Gen. Genet. 214 (3):456-459, 1988.
Spectinomymcin resistance conferred by mutations in the plastid rDNA gene in higher plants is known. Fromm, H., et al., EMBO J, 6:3233-3237, 1987.